SLUDGE is now open!

[Erwin_Br]

Tim Furnish, creator of the SLUDGE engine, has uploaded his source code to sourceforge and officially declared it open source. OpenSLUDGE is the name of this new project, and you can start tinkering with the engine right now.

Tim Furnish: "I know a lot of people have been waiting a long time for me to get back to working on SLUDGE rather than doing my day job (which is currently also an evening and weekend job, such is the joy of the games industry). Well, me too. But it doesn't look like it's happening any time soon so, for the meanwhile, why not have a tinker with the source code yourself? What's the worst that can happen?
 
Once a few people have given it a go and got the applications building, I'll start letting people commit their changes."

[ad7venture]

That's pretty cool.  I don't think I'll be messing with it, though.  I've got too many other things going.

[odnorf]

That's great news. Although it's not my engine of choice it's a very good move since Tim didn't have the time to update the engine himself. But I can see a rather big problem here. The license, which is GPL, forbids closed source games. Maybe the people who know Tim can suggest him to change the license (to lgpl for example, or any other os license which permits the usage without releasing the whole project as gpl too).

[Erwin_Br]

That's great news. Although it's not my engine of choice it's a very good move since Tim didn't have the time to update the engine himself. But I can see a rather big problem here. The license, which is GPL, forbids closed source games. Maybe the people who know Tim can suggest him to change the license (to lgpl for example, or any other os license which permits the usage without releasing the whole project as gpl too).

That might be a good idea. It didn't even occur to me, but you're right!

--Erwin

[Trumgottist]

But I can see a rather big problem here. The license, which is GPL, forbids closed source games. Maybe the people who know Tim can suggest him to change the license (to lgpl for example, or any other os license which permits the usage without releasing the whole project as gpl too).

While I'm not one of GPL's biggest fans, that shouldn't be a problem, and the licence is suitable here. The game code is clearly separated from the engine code. Many similar cases are found in IF, where it's common for the interpreters (i.e. the equivalents of the SLUDGE engine) to be GPL'd, while most of the games running in them are still closed source. Or for another example, look at ScummVM - it's also GPL'd.

[odnorf]

EDIT: I modified my post because I'm not sure. 

According to the gpl faq you are allowed to interpret scripts (and other data). But who will decide on the binding?

Q. If a programming language interpreter is released under the GPL, does that mean programs written to be interpreted by it must be under GPL-compatible licenses?

A. When the interpreter just interprets a language, the answer is no. The interpreted program, to the interpreter, is just data; a free software license like the GPL, based on copyright law, cannot limit what data you use the interpreter on. You can run it on any data (interpreted program), any way you like, and there are no requirements about licensing that data to anyone. However, when the interpreter is extended to provide "bindings" to other facilities (often, but not necessarily, libraries), the interpreted program is effectively linked to the facilities it uses through these bindings.

[Trumgottist]

Output of a GPL'd program is not a problem:
http://www.fsf.org/licensing/licenses/gpl-faq.html#GPLOutput
http://www.fsf.org/licensing/licenses/gpl-faq.html#WhatCaseIsOutputGPL

But I assume this is what you're referring to:
http://www.fsf.org/licensing/licenses/gpl-faq.html#IfInterpreterIsGPL

I'm no lawyer, and the language is getting complicated, but as far as I can tell, that should be no problem either.

EDIT: Seems we were browsing the FAQ at the same time.

The talk of "bindings" is about linking to GPL'd libraries, so it's not the same thing.

[odnorf]

(often, but not necessarily, libraries)

You are probably right, but it still looks gray and I wouldn't want to put the test on me.

[ad7venture]

You are probably right, but it still looks gray and I wouldn't want to put the test on me.

Blender is the same way and they give a good description.  All works created by Blender are the property of the person who made them.  They warn people about the game engine because there is a mixing of code at that point and when that happens, everything is GPL, if there is a definite separation, then your  work and your code are your own.  I wouldn't worry about it at all.  I'm not sure how something like this will work out for open source, though.  Usually users become interested in the source after using a program for a while, but if the language is different it's a lot of work for them to check into the source code.  Blender is like that and they do get a fair number of people that do a little work on the source, unfortunately, no one seems to touch the game engine except the guy that wrote the Bullet physics engine.

[odnorf]

It seems that Tim has changed the license. Now it's dual, GPL or LGPL which will cover all possible problems and won't scare anyone. And even more it adds new possibilities. Now you can link closed source libraries from the interpreter with no problems (bink video playback library comes to my mind as an example).

[Erwin_Br]

Awesome. 

--Erwin

[fiammy]

Great news. I'll go and check it out right away!

[ad7venture]

I just got in a discussion about that and linking is a problem with the GPL.  I didn't know it was that restrictive.  I guess LGPL is a lot safer.

[fiammy]

Correct. As far as the GPL is concerned, when you link a library with a program, that library becomes part of the program, and thus the entire program is to be considered GPL licensed. That's what Microsoft meant by 'viral license', once you introduce one GPL part in a program, it has impact on the entire codebase.

A few years back, I read some speculation about this. People were thinking that using a GPL program under Windows subjects the entire Windows you are using to GPL, as you invariably link to some part of the operating system you are using. Didn't hear much about that later though.

I had a look at sludge, and was a bit underwhelmed. It's still a major work in progress so not for the faint at heart.

[Trumgottist]

I had a look at sludge, and was a bit underwhelmed. It's still a major work in progress so not for the faint at heart.

Messing with the Sludge source code may not be for the faint of heart (as far as I know, I'm the only one besides Tim Furnish doing it), but using the Development Kit is pretty smooth (IMHO, of course - others will have differing opinions mainly because of its high reliance on scripting and lack of an IDE). I'm not sure what you mean by "major work in progress". The main reason I chose it for making Frasse was the high level of polish. It felt very solid to use.